Pneumatic tire



June 7, 1938. B F RANDEL 2,119,557

PNFQMATIYC TIRE Filed April 23, 1937 Figi- INVENTOR Bo TBLKE HANDEL BYATTORNEY Patented June 7, 193g UNITED STATES PATENT OFFICE 3 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) This invention relates to a non-skid tire and has for anobject to provide an yapproved tire having an extremely long non-skidlife.

'Ihe usual non-skid tire has a tread surface on its periphery which isworn away at a comparatively early time and as Soon as the nonskid treadsurface is worn away the tire becomes smooth and non-skid-proof and isusually discarded in spite of the fact that the side walls and remainderof the tire is still in substantially perfect condition, and capable ofproviding a great deal more wearing surface. The usual non-skid tire issubstantially circular in cross-section at its outer periphery, therebylimiting the depth of the non-skid grooves provided therein.

It is an object of this invention to increase the non-skid life of thetire by making it possible to provide extremely long lived non-skidgrooves or other non-skid means on the periphery of the tire by changingthe internal curvature of the periphery of the tire so that the internalcontour of the tire will have a re-entrant curve instead of theconventional substantially circular curvature. With such a re-entrantcurve the contour of the tire permits the provision of non-skid groovesor other non-skid means to the fullest thickness of the tire so that thenon-skid means will remain until the casing of the tire itself has wornout and is ready to be discarded.

With the foregoing and other objects in view, this invention comprisesthe combinations, constructions and arrangements of parts set forth,disclosed and claimed in the following specifica- 3 tion, taken inconsideration with the accompanying drawing, wherein like referencesdenote corresponding parts.

Fig. 1 is a plan view of a portion of the wear.- ing surface of thetire;

Fig. 2 is a section View on line 2-2 of Fig. 1,

Fig. 3 is a fragmentary view showing a cross cord tied to a longitudinalcord.

There is shown at I0 the tire of this invention having its side Walls IIof the usual construction, that is, having conventional cord or fabricreinforcements I2 therein and the usual bead I3, the pneumatic tube I4being located within the tire I0. The treated wearing surface I5 of thetire Ill is provided with a plurality of nonskid cups or grooves I6. Thecasing Il on which the wearing surface I5 is supported has a reentrantcurvature as indicated at I8, the thickness of the casing at Il beingsubstantially conventional.

The cups or grooves I6 are provided with a central longitudinal rib I9and two side longitudinal ribs 20 connected by short cross ribs 2lspaced from each other. A plurality of reinforcing cords or wires 22extend along. the central longitudinal rib I9, and reinforcing cords orwires 23 extend through the short ribs 2I, are tied to the central vribi cords 22 as shown, and merge into the side walls II of the casing.As a result of thus reinforcing the sides of the deep, separated cups or10 grooves I6, it is impossible for them to collapse under the action ofa side skid, and they thereby tend to maintain a uniform road traction.throughout their exterior tread surface, which substantially tends todiscourage side skidding. 15 Furthermore, the re-entrant curvature 24,which is beneath the said deep, separated cups or grooves I6 extendsupon opposite sides thereof, with the result that the lateral angles orfillets I8 at opposite ends of said re-entrant curvature 24 are directlybelow the outer margin of the exterior or tread surface of the ribs 2Il.The air pressure within the inner tube I4 in its thrust against there-entrant curvature 24 and its opposite terminal angles or fillets I8results in a 5 balanced pressure of the exterior or tread surface of theribs 20 in their road traction frictional effort, which precludes theserious fault of tires of the prior art in lateral skidding exertingtheir principal or sole road traction upon 30,

one of the lateral edges of the road traction surface of the tire,whereas, in my invention the road traction surface is under allcircumstances maintained with uniform stressed contact with the roadsurface. Although the tread or wearing surface I5 just described is thepreferred form of non-skid surface to be used on this invention, it willbe apparent that other types of non-skid surfaces may be provided hereonwith their nonskid grooves and treads greatly increased in thickness andin depth as a result of the presence of the re-entrant periphery I1.

Likewise, while the tube I4 may be of the conventional shape it isapparent that it may be especially shaped and provided with a similarre-entrant curvature 24 corresponding to the reentrant curvature at Il.The central longitudinal rib I9 might be omitted without affecting theoper-ation of this invention, in which case the cross ribs 2l wouldserve to maintain the proper contour of the tire.

As the tread surface I5 is Worn away in use it will be apparent that anon-'skid surface will be maintained until the casing itself is wornthrough substantially to the tube at the re-entrant anglecompressionvYY-on"eachv cup increases. I-Iowever,l

, Y 25 Y ventstlre tire from' heatingby suchair removing heatifrortheatire. l,

Va: Y'

I'8, for theV openings in the non-skid surface extend to a point belowthe line extendingbetween the two re-entrant angles I8, thus insuringthat the non-skidsurface will last for the entire life of the tire andpermitting the maximumV non-V skidmileageY therefrom.-

In'theYV treadY disclosed as anY illustration of my invention, itlwillrbejnoted that the extended depth of the grooves I6 allowsfairpressure to build uptherein as the treadyieldsunder lo'ad on hardpavement', preventing the formation yof theVA vacuum present in the'oldstyle of vacuum cup l .When used on muddyV roads the pressure-w tire.prevents the mud from filling the grooves, andV serves to' forceVA outtheV mud immediately, when the groove is removed fromV the mudv by theVrotation of the wheel. Y

In my'invention, the'road surface ofthe tire comprises a large Volume ofcompressed air in separate volumes of such dimensions that the airVentrapped inreach volumejis maintained therein.iintilreleasezl-by therotation? of the wheel' withoutiexerting any :vacuumv pull' uponthe roadsurface. The. large@ volumeffofV air en-f tering gand.V leaving suchseparate volumesVVV pre- 'Furthermore in the old Y load compression Yofsuch ltires caused 'some Vair toY be forcedfrom' each ofrsuchcupsraskthe Yload asV the loadY compression decreases by the wheel rotation apartial vacuumV is `formed which re-y quires .substantial power toovercome,V exerts` harmful V'effect upon theroad surface, and causesv -Vobjectionable noise," due to the successive break-l vacuum cup tires'theY trated and described what I now consider to rep.-V

resent its best embodiment. However, I desireto have it understood thatwithin the scope ofthe appended claims the invention'may beV practiced Yotherwise than as specically illustrated and de- Y.

scribed. f

`The invention Yherein described and claimed y maybe used and/ormanufactured by orffor the Government of the United States of Americaforl VGrovernmental VVpurposes without the payment of jany royaltiesthereon or therefor.

"I' claim: Y Y Y Y u 1; A; pneumatic tire casing comprising sidere-entrant curvature, the edges of said peripheral surface'meeting saidside Walls at a substantially acute angle,ra line extending between theapices "of the acute angles 4formed by there-entrant curvature and theside Walls intersecting theY oute Y sideV of saidl -peripheral surface.Y .241AY pneumatic tire casing comprising vside walls anda treadsurface,rar` peripheral surfaceco'nnectingrsaid side walls andsupporting' saidV YWalls anda tread surface, a peripheral surface iconnecting said side Walls and supporting said v tread surface-'saidperipheral surfacehaving a tread surface, saidjperipheral Ysurface*havingaj re-'entr'antcirvature zthe edgesY of sz'ajidperipheralvsurface meeting said sidewalls iat a substantially acuteangleg`alineextending betweenV the apices o'f theV acute angles Vfornedbyftherre-entrant curvature andvv the sideyrwalls intersecting the outerside of said.' Vperipheral.surface. and Y the j non-skidlwearing tread'.Y v

Y- 3. A non-skid pneumatic tire comprising resideA walls,aperipheralsurface connecting saidside walls with a re-entrant curvatureanda non-skid Y t tread supported on said peripheral `surface, saidnon-'skid wearing treadV extending 4to' a poi-nt belowa linecorinfectingv the acute angles` formed between the re-entrant curvatureof vthe periph-Y eral' surface and'saidv side walls. Y Y Y Y Bo FOLKERANDEL.y

